Service-observing equipment for telephone systems



Aug. 30, 1927. 1,640,675

M. SCHWARTZ SERVICE OBSERVING EQUIPMENT FOR TELEPHONE SYSTEMS Original Filed July 10, 1922 Inu5n UI----- y Ffiuhaal EEhW Patented Aug. 30, 1927;

UNITED STATES MICHAEL SCHWARTZyOF'CI-IICAGO, ILLINOIS, ASSIGNOR, BY

ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- T AUTOMATIC WARE. j

SERVICE-OBSERVING EQUIIMENT FOR TELEPHONE SYSTEMS.

Application filed July 10, 1922, Serial No. 574,038. Renewed June 6, 1927.

connected to the observing equipment-only when a call is initiated.

Another feature of the invention is the provision of means for enabling the observation operator to disconnect the observing equipment from a busy trunk line and place it in condition to be associated with the trunkline next used.

A further ob ect of the invention 1s to provide improved arrangements, whereby the operator may hold up the connection on a trunk line for testing, purpose.

There are other objects of the invention which have not been mentioned, but which, together with the foregoing, will be deor any desired scribed in the detailed description which is,

to follow, taken in conjunction with the accompanying drawing.

Referring now to the drawing, in the upper left hand corner is shown a portion of the circuits of an ordinaryStrowger vertical and rotary connector switch,

The relay groups E and E are two of a plurality of such groups which may number ten, assuming that ten trunks is the maximum number which the operator can observe the traftic over. There is'one relay group such as E for each trunk line of the ten under observation, all the relay groups being preferably mounted as a unit. The leads from the relay groups extend to terminals and the trunk lines over which it is desired to observe the traffic are temporarily connected to these terminals. Each relay group functions to connect its associated trunk line to the operators observing equipment when the trunk line is seized, assunr.

ing of course, that the observation equipment is idle. lhe op'erators observing equipment 0 ascertain what number is dialled by a calling subscriber, she is provided also with the any well-known type.

While in the drawings only two trunk lines have been shown connected up for ob servation, it will be understood that there will be ten of these in the case assumed-and that those not shown will be connected up in the same manner as the one illustrated.

Having briefly described the apparatus shown in the drawing, a detailed explanation of its operation will now be given. For this purpose it will be assumed that the trunk line comprising conductors 12, inclusive, is seized by anautomaticselector switch. I

Immediately after this operation the line relay 16 of the connectorI-I is energized, and operates to close the circuit of its associated slow acting release relay. The latter relay operates to prepare the impulsing circuits of the connector H and also to place ground upon the release trunk conductor 11, thereby establishing a holding circuit for the preceding switches.

The grounding of release trunk conductor 11 closes a circuit which extends from the said conductor by way of terminal ll, and through the winding of the relay to battery. Assuming now that the service observing equipment O is idle at the present time, the energization of relay 50 has the following results At armature a circuit is closed, which may be traced byway of the said armature and its front contact,

springs 65, through the upper winding of relay 51, armature 62 and its back contact, armature 115 and ltsback cont-act, resting contact of spring 132 of keyK andthe said spring to battery. The relay '51 is energized over, the above circuit and operates its armature 63 to establish a locking circuit for itself through its lower winding over a circuit which extends from ground by. way of armature 60 and its front con- ,tactfarniature 63 and its front contact,

MESNE assrenmnnrs,

tape registering device R, which may be of through the lower winding of the relay 51, back contact and armature 116, and through the winding of the relay 101 to battery. Other results of the energization .of relay 51 are that at armature 62 the original energizing circuit for its upper winding is opened and also the energizing circuits for other similar relays associated with other trunk lines, and at armatures 61 and 6a the line conductors 10 and 12 are associated with the conductors 135 and 136 leading to the observing equipment 0. The lamp L is also lighted by a circuit in multiple with that for the lower winding of relay 51. The relay 101 is energized in series with the lower winding of relay 51. and operates its armature 117 to close a circuit extending from battery, by way of resistance 13?, armature 117 and its front contact, through the winding of relay 100, and through the winding of the high resistance relay 102 to ground. Only the relay 102 is energized over the above circuit. Upon operating, re lay 102 at armature 120 closes the circuit of the lamp L whereby the operator is notified that a trunk has been associated with her observingequipment. The lighting of the lamp L also serves to notify her what trunk line is associated with the observing equipment. Assuming that the key K is thrown at the present time, as it ordinarily will be, it will be seen that the right hand winding of the operators induction coil is bridged across the conductors 135 and 136 in multiple with the high resistance polar ized relay 10%, the latter being in series with the'high resistance 130. Polarized relay 104 is not operated at this time due to the fact that its winding is practically shunted by the circuit through the'calling subscribers telephone. On account of the relative number of turns between the primary and secondary of the operators induction coil, the elficiency of the operators listening circuit is not very high as it is only necessary for her to monitor the connection.

The calling subscriber may now operate his calling device in accordance with the next digit of the desired number. operation, a series of interruptions is produced in the circuit of'the line relay 16 of the connector H. By the operation of this relay the vertical magnet is closed to raise the switch shaft carrying the wipers 25-27, inclusive, step by step until these wipers are placed opposite the level of bank contacts in which is located the contact set associated with the line of the called substation.

Each time an interruption is produced in the circuit of the line relay 16 the shunt circuit around relay 10 iis opened and this relay operates its armature 122 thereby closing a circuit for the slow acting relay By this 103 and also for the relay 106 of the recorder R. Relay 106 of the recorder R, accordingly operates to, set down on-the tape the number dialled. The slow acting relay 103 attracts its armature 1.21 and maintains it attracted throughout the series of interruptions, thereby short circuiting the secondary of the operators induction coil so that no disagreeable noise is produced in the operators receiver by the dial interrupt-ions.

The calling subscriber will now operate his calling device in accordance with the next and final digit in the desired number. As before, a series of interruptions is produced in the line circuit of the line relay 16. This relay now controls the operation of the rotary magnet in rotating the switch wipers into engagement with the bank contacts associated with the desired line which, we will assume are the bank contacts 28-60, inclusive.

This last series of interruptions also actuates the polarized relay 104C in the observing equipment in th same manner as before, and the relay 106 of the recorder is operated to indicate the number on the tape. In this manner the operator is informed of the number called.

If the desired line is busy connection will not be completed with the called line, and a busy tone will be given to the calling subscriber. This tone is also audible to the observing operator.

i-issnming that the desired line is idle when the wipers of the connector are brought into engagement with its bank contacts, the connection is completed and ringing current is intermittently projected out over the called line to signal the subscriber at the substation thereon. lVhen an answer is obtained the back bridge relay 15 energizes'over the called line loop and reverses the direction of current flow over the conductors 10 and 12 for metering or supervisory purposes. Due to the fact that the relay 10a is polarized, this relay is not operated by the current reversal. As the operators head set is associated with the trunk line, she may listen to the conversation as long as she desires.

lVhen the operator desires to disassociate the observing equipment from the trunk line, she operates the release key K. By this operation the winding of the high resistance relay 102 is short circuited by direct ground through spring 138 and its working contact. By this operation the slow acting relay 100 is energized and the relay 102 deenergized. Upon deenergizing, day 102, at armature 120 extinguishes the lamp L Relay 100, upon operating, at armature 116 opens the circuit of the relays 51 and 101. Upon deenergizing, relay 51 disconnects the trunk line comprising conductors 1012, inclusive, from the observing equipment. Due to the fact that the relay 50 has its armature attracted, the relay 51 cannot again be enerrelay 101 deenergizes as its'circuit is opened and opens th circuitof the slow relay 100, which also deenergizes after a short interval. The observing equipment is thus restored to normal and may again be seized.

It will be observed that a trunk line which has been seized prior to the release of the observing equipment cannot now' be associated with it for the reason that the associated'relay such as 52 will 'be fully energized, and consequently, no circuit can be completed for the relay such as 53. The relays such as 50 and 52 can only complete a circuit for their cooperatin relays 51 and 53 while they are energizing. Consequently, onlytrunk lines which are just seized are connected to the observing equipment even though theequipment is idle. This insures that the operator will always observe initiated calls.

It will be understood that the operator vill recordthe data gained by listening in on the connection in any desired manner.

It should be noted that it a call is initiated on one ot the trunks of the group while the tion, when the trunk line comprising con ductors 1012, inclusive, is associated with it, it will be assumed that the operator desires to hold up this connection due to the fact that the subscriber calling has encountered trouble, or for any other reason. In order to do this the operator will operate the holding key K By this operation battery is removed from the energizing circuits ofthe upper windings of relays such as 51 andis supplied to the operators transmitter. In addition, the relav 105 is bridged across the I conductors 10 and 12 ot the trunk linecin order to maintain the line relay 16 energized exclusive ot the calling subscribers control.

Relay 105 is energized in series with the line relay 1-6 and operates at armatures 123, 124: and 125, to disconnect the secondary of the induction coil I and to connect the ordinary onerators circuit P to the line. The operator may now converse with the calling subscriber and give him any information she desires. The connection W111 be held up as long as the operator maintains the key K thrown, even v though the subscriber calling hangs up.

' described.

scribers lines are connected up for observa- Attention is now directed to the fact that while in the drawing only atrunk line extending from a connector switch is shown connected up with the observing equipment, itwill be understood that a selector trunk 5 line or any other trunk line overv which it is desired to observe the traliic can be connected up in a like manner, and the opera tion will besubstantially the same as above This also 1s true. even 1t subtion, the operation being the same in all cases. p

It should be notedalso that the operatoris enabled to render th observing equipment O inaccessible to calling'lines by merely operating the key 1 whenever the observing equipment is not in use. By this operation battery is removed from the energizing circuits of all the relays such as 51, so that none of them can be operated by a call being initiated. I

The features of the invention having been described, what is considered to be new and desired to have protected by Letters Pat-entwill be pointed out in the appended claims.

lVhat I claim is:

1. In a telephone system, a plurality of trunk lines, each of said plurality terminating in an automatic switch, operators equip-. ment, subscriber controlled means for seizing any trunk line of said plurality and for operating the associated automatic switch, means responsive to such seizure for connect-ing said seized trunkline to said equipment, and'a registering device associated with said equipment operated in synchro- I11S1'1'l with said rlSSOClfllZQCl'ElUiJOIDiLlZlC swltch.

'2. In a telephone system, a. plurality of V operating the associated automatic switch,

means controlled by such seizure for connecting said seized trunk line to said equip-- ment, :1. registeringdevice associated with said equipment operated in synchronism with said associated automatic switch. and means operative during the operation of said device for renderingsaid equipment inetl'ec tive.

3. In a telephone system, a plurality of trunk lines, each of said plurality terminate ing in an automatic switch, operators equipment, subscriber controlled means for seiz ing a trunk line of said plurality and for operating the associated automatic switch, means controlled by such seizure ,tor' connecting said seized trunk line to said equip ment, a registering device associated with said equipment operated in synclnonism said key for permanently disconnecting said equipment from said trunk line long as said associated switch remains operated. d. In a telephone system. a plurality of trunk lines, each of said plurality terininat ing in an automatic switch, operators equipment, subscriber controlled means for seizing atrunlr line oi said plurality and for operating the associated automatic switch, means controlled by such seizure for connecting said seized trunk line to said equipment a registering device associated with said equipment operated in synchronism with said associated automatic switch, means for releasing said associated automatic switch, and operator controlled means for preventing said release.

5. In atelephone system, a. plurality of trunk lines, each of said plurality terminating in an automatic switch, operators equipment, means for seizing a trunk line in said plurality, means controlled over said seized trunk line for operating the associated automatic switch, means controlled by said seizure for connecting said seized trunk line with said equipment. means for seizing another trunk line of said plurality, means for preventing the last seized trunk line from being connected with said equipment, means for releasing the first seized trunk line, and relay controlled means for further preventing the second seized trunk line from being connected to said equipment.

(3. In a telephone system. a plurality of trunk lines, a release conductor for each of said trunk lines, means for grounding one of said release trunks, opcrators equipment, relay controlled means operative by said grounding for connecting the trunk line having the grounded release trunk to the opperators equipment, means for grounding other release conductors in said plurality of trunk lines, means for preventing any of the other trunk lines having grounded release conductors from being connected with said equipment, means for rendering said equipment selectable. and means for further preventing any or the other trunk lines having grounded. release trunks from being connected to said equipment.

7. In a. telephone system, a group of trunk lines each terminating in an automatic switch, monitor equipment common to said trunk lines, said equipment comprising an operators listening circuit and a register, means for connecting said monitor equip m-ent with a trunk line when the same is taken for use by a calling subscriber, means for operating said register at the same time that the switch associated with the connect ed trunk is operated by said subscriber. and means for rendering said listening circuit inoperative while said register is operating.

8. In a telephone system, a group of trunk lines, operators equipment for monitoring calls extended over said trunk lin s,

nected to said equipment while the trunlt' first taken for use remains connect-ed.

. 10. In a telephone system, a grouper" trunk lines, operators equipment for mon'i- V toring calls extended over said trunlr lines, means effective only at the moment a trunk is taken for use for connecting such trunk to said equipment, and means for prevent-- ing trunks taken for use subsequently and still in use from being connected with said equipment when the trunk first taken for is disconnected from said equipment.

11. In a telephone system, a group of trunk lines, operators equipment for moni toring calls extended over said trunk lines, means effective only at the moment a trunk is taken for use for connecting such trunk to said equipment, and means for disconnecting any connected trunk tromf said equipment at the will ofthe operator.

12.111 a telephone system, a group of trunk lines, operators equipment for moni toring calls extended over said trunk individual relays for connecting said trunk lines with said equipment, and means "for preventing the energization of any connecting relay except at the moment the associated trunk line is taken for use.

13. In a telephone system, a group of trunk lines, operators equipment for monitoring calls extended over said trunk lines; individual relays for connecting said trunk lines with said equipment, means for energizing a connectin relay when the associated trunk line is taken for use, and means for preventing the energization of connectmg relay associated with a trunk line already in use when the connecting relay first energized is dcener ized, said ineans comprising a device individual to each connecting relay arranged to transmit a momentary impulse to its associ: d connecting relay when the associated trunk is taken for use.

14. In a telephone system, a group of trunk lines, operators equipment for monitoring calls extended over said trunk lines, individual relays for connecting said trunk lines with said equipment, individual line relays for operating said connecting relays, and means for preventing any connecting relay from responding to its associated line relay unless the latter isenergize'd while the said equipment is idle, said means including contacts on each connecting relay for openlines,-

ing the circuits of the other connecting relays. p p

15. In a telephone system, a group of trunk lines, a branch line common to the trunk lines of said group, and means effective only at the moment a trunk line is taken for use for connecting such trunk line with said branch line.

16. In combination, a group or connecting relays, locking circuits for said relays, a conductor common to said locking circuits, a relay included in said conductor, a second rela a circuit for said second relay prepared by said first relay, a keyfor closing the circuit of said second relay, and contacts on said second relay for opening said common conductor. c

17. In combination, a group of connecting relays, operators' monitor equipment multipled to contacts of said relays, energizing,

circuits for said relays, a conductor common to said circuits extending to a source of cur-f rent, and operator controlled means for disconnecting said conductor from said source.

18. The combination, with an automatic switch operated by interruptions in a closed control circuit, of an impulse repeating relay and a resistance in series therewith bridged across said control circuit and inoperative as long as the circuit is closed, and a second circuit, said'repeating relay being adapted to energize to control said second circuit each time said control circuit interrupted to operate said switch.

19. The combination, with an automatic switch operated byinterruptions in a closed control circuit, of an impulse repeating relay and a resistance in series therewith bridged across said control circuit, said relay and resistance being shunted as long as the circuit is closed, a second circuit 'controlledby the energization of said relay each time said control circuit is interrupted to operate said switch, and a pen register controlled over said second circuit.

20. In a telephone system, aline terminating in an automatic switch, a closed control circuit for said switch including a line relay connected in series with a battery, means "for producing a series of interruptions in said circuit to operate said line relay, an impulse repeating relay bridged across said line in series with a resistance, and means controlled by said repeating relay to record the number of impulses.

In witness whereof, I hereunto subscribe my name this sixth day of July, A. 'D., 1922.

MICHAEL SCHWARTZ. 

